Pulverizer



Feb. 22, 1944.

L. N. DOYLE PULVERIZER Filed Aug." 30, 1943 2 Sheets-Sheet 1 m Wm WM h.l I Q m Z 2 2 kkmx 5 N? ww m w, m. 3 w m 1 M N Feb. 22, 1944. L DOYLE2,342,255

PULVERIZER Filed Aug. 30, 19 43 2 Sheets-Sheet 2 INVENTOR.

TOR EV Patented Feb. 22, 1944 UNITED STATES PATENT OFFICE PULVERIZERLawrence N. Doyle, Wollaston, Mass.

Application August 30, 1943, Serial No. 500,461

3 Claims.

The invention relates to animprovement in pulverizers for the reductionof materials to a finely ground state.

The object of the invention is to obtain greater efliciency in theoperation of the pulverizer and lower operating costs, first, byproviding a construction which will assure of a positive layer ofmaterial on the grinding surface at all times without the necessity ofrotating the grinding surface at high speed to maintain this material ina position to be pulverized, second, to retain this material in thisposition until it has passed several times beneath the rolls, third, toprovide a construction which will better serve to get the fine materialinto a swirling suspension within the grinding chamber after thegrinding operation and before its deposit on the floor of this chamber.

The invention can best be seen and under stood by referring to thedrawings in which- Fig. 1 is a vertical section of the machine, and Fig.2 is a section on the line 2--2 of Fig. 1. I represents the machinebody, or housing, which forms within it a relatively deep pit or cavitywithin which is contained many of the operating parts later to bereferred to. The body is made of a strong and rugged structure, and ismounted upon any suitable base, not shown. Mounted upon the outer shellof the body is a superstructure 2 which lead to a separator, not shown,as it may be one of known construction.

Located within the pit is a disk-like rotatable table 3. This table isarranged to turn upon a hub 4 which forms part of an auxiliary bodycasing affixed to the body 1, suitable bearings 6, for reducingfriction, being interposed between the table and hub. The table isrotated by a mainvertical shaft 8 which extends through the hub, and isotherwise suitably secured to turn within and upon the auxiliary bodycasing. The shaft 8 has aflixed to it a main drive gear 9 which isdriven by a pinion Iii borne by ashaft II which turns within a bearingon the auxiliary body casing and is itself driven from any suitablesource of power, not shown.

The table 3 forms the bottom of the grinding chamber I3. The table is oflesser diameter than that of the housing within which it i contained, inorder to leave air space between the table and the body housing whichencloses it. Mounted upon the table is an air turret l4 upon which ismounted a grinding ring l5, all of whichtable, turret, and ringrotate asa unit in relation to the grinding chamber. The table and turret arenecessarily made of a strong rugged structure, preferably an integralcasting, in order to bear the crushing strain to which the grinding ringis subjected, and provide ample support for this ring.

The air turret I4 is made up of annular spaced top and bottom sectionsi5 and ll, respectively, between which are interposed spaced vanes l8diagonally arranged in order that air may pass through the ports betweenthese vanes in tangential direction.

The grinding ring [5 rests upon the top section [6 of the air turretwhich provides a setting for it. The ring in retained againstdisplacement by a flange i9 rising from the inner edge of this sectionIt and against which the inner edge of the ring has bearing. Thegrinding ring is also retained by a plate or guard 29 against which theouter edge of the ring has bearing. This guard is detachably secured tothe top section i6 of the air turret in any suitable manner. It is madea removable guard in order to facilitate the removal of the grindingring, for the grinding ring is a removable ring.

The grinding ring 15 is a concaved ring. The general concavity is at anangle, preferably of about 265 angle from the horizontal. The inner edgeof the concavity lies substantially flush with the top of the flange l9against which the inner edge of the ring has bearing. Thence there is aslight dip in the concavity with relation to this edge, and thence theconcavity rapidly rises by reason of its inclination, with the backportion of the ring made relatively deep. Thus the grinding ring is onein which the material to be worked upon will hold to the ring withoutundue outward displacement, although the material is subjected to someslight degree of outward displacement on account of centrifugal forcedue to rotation of the ring which in practice is rotated at a speed ofpreferably 40 to 50 R. P. M. In any event the material will not escapeover the back side of the ring due to the overhanging lip 22 of theguard which will operate to throw any sufficiently outwardly displacedmaterial back onto the ring.

25 are the crushing rollers with rounded faces which engage the concavedsurfaces of the ring for crushing material thereon. Four rollers arepreferably provided. Each roller is borne by a shaft 26 turned within abearing 2'! on a rocker 28. This rocker is journalled to turn in abearing 23 on a bed 39 on the top of an auxiliary fixture 31 forming apart of, or attached to, the body 1 of the machine. Each rocker haspivotally secured to it a shaft 32 passing through an opening in the topof the fixture 3i and through a plates? within the fixture. The shaft isunder the control of a spring 34 with adjusting nuts 35, 35 upon theshaft engaging the plate and spring, respectively, by which the springmay be adjustably tensioned to draw the crushing roll hard against thesurface of the grinding ring.

The material to be crushed is deposited within the machine through ahopper 38 from which by bolting to the body of the machine by hangers 4|which extend over the guard of the grind ing ring and hold each scoop inposition. Re-- jected material from the separator will be returned tothe grinding ring through a spout 42.

Formed within the pit with location outside the air turret l4 encirclingthis turret is an annular air chamber 43. Compressed air is introducedinto this chamber whence it escapes to pass between the vanes of the airturret into the grinding chamber. The bottom of this air compressionchamber is closed from the main chamber of the pit by an annular plate44 fixed to the body The top of the chamber 43 is closed by an extension45 from the top section l6 of the air turret which slidably co-ordinateswith a flange 46 extending from the body of the machine, a seal 4'! ofthe grease type being formed between these parts in order to seal theair in the compression chamber. The compression chamber 43 is preferablymade contracting from the point where air under compression is admittedto it, in order that the force of the air passing through the ports ofthe air turret will be as uniform as possible for all the ports.

The general operation is as follows:

A the grinding ring is rotated the crushed material, after having passedunder several rolls, will discharge over the inner side of the grindingring into the grinding chamber, falling in a thin sheet or blanket bythe outlet ends of the ports of the air turret. The ring is rotated in aclockwise direction and the blanket of material. discharging from itwill, as it falls, have like direction, which direction is reverse tothe direction of the air entering tangentially through the ports of theturret. Accordingly the entering air will strik the falling materialwith explosive action and separate out the fine before it hasopportunity to fall onto the floor of the grinding chamber, the ensuingaction of the air being one in which the particles borne by the air insuspension circulate within the grinding chamber in a swirling actionand are afterwards carried up and drawn into the separator. During thisoperation there is little to impede the free course of the air. Thegrinding rolls not only lie outside the grinding chamber and, inasmuchas these rolls are being rotated through the rotation of the ring with arelatively slow rotation, no reactive air currents will be created tointerfere with the free course of the air. The rotation of the airturret itself, though counter to the direction of the entering air, willenable the entering air to engage the blanket of falling material withsubstantial unbroken continuity throughout the entire circle, asdistinguished from a construction in which the turret is stationary, ifit were possible to use a stationary turret with a rotating grindingring. In such case the necessary size or thickness of the blades of theturret, in order to provide necessary support for the grinding ring,would in a measure a housing, a rotary table mounted within the housing,an air turret with ports tangentially arranged mounted upon said tablein surrounding relation to a grinding chamber, a crushing ring mountedupon said turret, said ring being adapted and arranged whereby thecrushed material will fall from 011' the inner edge of said ring throughsaid grinding chamber and by the outlets to the ports of the air turret,a set of crushing rolls, means for maintaining said rolls in engagingrelation to said ring, means whereby compressed air will be directed topass through the ports of said air turret into said grinding chamber,and means for rotating said table, air turret and crushing ring as aunit wherebythe material falling from said ring will move, during therotation of said ring, in a direction reverse to the direction of theair entering through the ports of said air turret.

2. In a pulverizer the combination comprising a housing, a rotary tablemounted Within the housing, an air turret with ports tangentiallyarranged mounted upon said table in surrounding relation to a grindingchamber, a crushing ring mounted upon said turret, said ring having aconcaved face angularly arranged with inclination towards the inner edgeof said ring whereby material to be crushed will tend to hold to saidring and crushed material will fall from ofi the inner edge of said ringthrough said grinding chamber and by the outlets to the ports of the airturret, a set of crushing rolls, means for maintaining said rolls inengaging relation to said ring, means whereby compressed air will bedirected to pass through the ports of said air turret into said grindingchamber, and means for rotating said table, air turret and crushing ringas a unit whereby the material falling from said ring will move, duringthe rotation of said ring, in a direction reverse to the direction ofthe air entering through the ports of said air turret.

3. In a pulverizer the combination comprising a housing, a rotary tablemounted within the housing, an air turret mounted upon saidtable insurrounding relation to a grinding chamber, said turret having ports fordirecting air into said grinding chamber, a crushing ring mounted uponsaid turret, said ring having a concaved face angularly arranged withinclination towards the inner edge of said ring whereby material to becrushed will tend to hold to said ring and crushed material will fallfrom ofi the inner edge of said ring through said grinding chamber andby the outlets to the ports of the air turret, a set of crushing rolls,means for maintaining said rolls in engaging relation to said ring,means whereby compressed air will be directed to pass through the portsof said air turret into said grinding chamber, and means for rotatingsaid table, air turret and crushing ring as a unit.

' LAWRENCE N. DOYLE.

